From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
 id DF174395BC3D; Fri, 13 May 2022 17:42:10 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org DF174395BC3D
From: "cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/91217] [9 Regression] Returning std::array from lambda
 results in an extra copy step on return
Date: Fri, 13 May 2022 17:42:10 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: c++
X-Bugzilla-Version: 8.1.0
X-Bugzilla-Keywords: missed-optimization
X-Bugzilla-Severity: normal
X-Bugzilla-Who: cvs-commit at gcc dot gnu.org
X-Bugzilla-Status: ASSIGNED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: jason at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 9.5
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-91217-4-OFtdhbV9Ab@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-91217-4@http.gcc.gnu.org/bugzilla/>
References: <bug-91217-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-BeenThere: gcc-bugs@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc-bugs mailing list <gcc-bugs.gcc.gnu.org>
List-Unsubscribe: <https://gcc.gnu.org/mailman/options/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-request@gcc.gnu.org?subject=help>
List-Subscribe: <https://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Fri, 13 May 2022 17:42:11 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D91217

--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-9 branch has been updated by Jason Merrill
<jason@gcc.gnu.org>:

https://gcc.gnu.org/g:da999d938e516ff12b39a0aa7e8f6d97fbee60df

commit r9-10177-gda999d938e516ff12b39a0aa7e8f6d97fbee60df
Author: Jason Merrill <jason@redhat.com>
Date:   Sat Apr 3 01:07:36 2021 -0400

    c++: NRV in lambda in template [PR91217]

    tsubst_lambda_expr was producing a function with two blocks that claime=
d to
    be the outermost block in the function body, one from the call to
    start_lambda_function in tsubst_lambda_expr, and one from tsubsting the
    block added by start_lambda_function when we first parsed the lambda.  =
This
    messed with the named return value optimization, which only works for
    variables in the outermost block.

    gcc/cp/ChangeLog:

            PR c++/91217
            * pt.c (tsubst_lambda_expr): Skip the body block from
            DECL_SAVED_TREE.

    gcc/testsuite/ChangeLog:

            PR c++/91217
            * g++.dg/opt/nrv20.C: New test.=